Sheet feed device and image recording apparatus having such sheet feed device

ABSTRACT

A sheet feed device includes a first sheet cassette having an accommodating portion accommodating a first plurality of sheets and a second sheet cassette, disposed on the first sheet cassette, accommodating a second plurality of sheets. The sheet feed device also includes a sheet feeder configured to selectively feed the first plurality of sheets and the second plurality of sheets toward a sheet feed path, and a sheet separator configured to separate, one by one, the sheets fed by the sheet feeder. Specifically, the second sheet cassette is configured to move above the accommodating portion and with respect to the sheet feeder between a sheet feed position in which the sheet feeder contacts sheets accommodated in the second sheet feed cassette to a non-sheet feed position in which the second sheet feed cassette prevents the sheet feeder from contacting sheets accommodated in the second sheet feed cassette.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent ApplicationNos. 2005-99607, 2005-99608, 2005-99609, and 2005-99610, each of whichwere filed on Mar. 30, 2005, the disclosures of which are incorporatedherein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a sheet feed device thatincludes a first sheet cassette and a second sheet cassette disposed onthe first sheet cassette, and selectively feeds sheets (recording media)that are positioned in the first sheet cassette or sheets that arepositioned in the second sheet cassette and are different than, e.g.,smaller than, the sheets in the first sheet cassette. The presentinvention also relates to an image recording apparatus having such asheet feed device.

2. Description of Related Art

A sheet feed device used in a known image recording apparatus, such as aprinter and/or a facsimile machine, is disclosed, for example, inJapanese Laid-Open Utility Model Publication No. 6-49439. In this knownsheet feed device, the sheet cassette for accommodating a stack ofrecording media (such as recording sheets and cut sheets) is disposed ina lower side of the apparatus body (housing). A cover member covering arear half of the sheet cassette is provided with a pair of guide holeselongated in the sheet feed direction, and the cover member is furtherprovided on its upper surface with a pair of regulation plates forpositioning the right and left sides of a manually fed sheet. Apartition plate is disposed in an accommodating portion of the sheetcassette so as to divide a front opening into upper and lower spaces. Apair of levers projecting from the upper surface of a rear portion ofthe partition plate are fitted loosely in the pair of guide holes. Asheet feed roller is disposed above the front opening of the sheetcassette. With this device for recording an image on a manually fedsheet, a sheet is placed at a predetermined position of the partitionplate, and the partition plate is moved forward so that its upper frontportion is placed below the sheet feed roller. Thus, the sheet may befed by the sheet feed roller. On the other hand, when the partitionplate is moved backwards, the sheets stacked in the sheet cassette arefed one by one by the sheet feed roller in cooperation with a pair ofseparation pieces provided near the front corners of the sheet cassette.

Another sheet feeding device is disclosed in Japanese Laid-Open PatentPublication No. 11-59925. In this known sheet feed device, a sheet feedroller is disposed above the front end of a first sheet cassette. Thefirst sheet feed cassette has a plate-like cassette base on which astack of sheets are placed, and the cassette base is pushed up towardsthe sheet feed roller by a coil spring provided at the lower frontportion of the cassette base. The cassette base is disposed between apair of side regulation plates that are movable to contact and toposition the right and left sides of the sheets in the first cassette. Aplate-like second sheet cassette is detachably attached onto thecassette base. The second sheet cassette has fixed side regulationplates and a fixed rear end regulation plate that contact and positionthe sheets in the second sheet cassette. The sheets in the second sheetcassette are smaller in size than those in the first sheet cassette.

However, in the sheet feed device disclosed in Japanese Laid-OpenUtility Model Publication No. 6-49439, because the partition plate doesnot include any separation pieces for separating one manually fed sheetfrom the other manually fed sheets, only a single, smaller-sized sheet,such as a postcard, is allowed to be placed on the partition plate.Consequently, in order to record an image on a plurality of postcards,it is necessary for the user to place one postcard at a time on thepartition plate, and to move the partition plate back and forth, whichis burdensome to the user.

Moreover, in the sheet feed device disclosed in Japanese Laid-OpenPatent Publication No. 11-59925, although a plurality of smallersized-sheets may be accommodated in the second sheet cassette, thesecond sheet cassette must be detached from the first sheet cassettewhen image recording is performed on larger-sized sheets. For example,when trial recording is performed on a plain sheet in the firstcassette, in order to check the position and color conditions of arecorded image before actual recording on a postcard, the second sheetcassette must be detached from the first sheet cassette and thenreattached to the first sheet cassette. In other words, it is notpossible to feed sheets in the first sheet cassette that are differentin size from those feed sheets in the second sheet cassette, in a statewhere the second sheet cassette is set in the first sheet cassette.Consequently, the user must attach and detach the second sheet cassetteeach time that the sheets to be used are switched, which is burdensometo the user.

SUMMARY OF THE INVENTION

Therefore, a need has arisen for sheet feed devices that overcome theseand other shortcomings of the related art. A technical advantage of thepresent invention is that the sheet feed device is relatively simple instructure, and can selectively feed different types of sheets, e.g.,sheets having different sizes, from two sheet cassettes while reducinguser interaction with operating the sheet cassettes.

According to an embodiment of the invention, a sheet feed devicecomprises a first sheet cassette comprising an accommodating portionconfigured to accommodate a first plurality of sheets, and a secondsheet cassette disposed on the first sheet cassette and configured toaccommodate a second plurality of sheets, in which at least onecharacteristic of the first plurality of sheets is different than atleast one characteristic of the second plurality of sheets. The sheetfeed device also comprises a sheet feeder configured to feed the firstplurality of sheets and the second plurality of sheets in a sheet feeddirection toward a recording unit, and a sheet separator configured toseparate, one by one, the sheets fed by the sheet feeder. Specifically,the second sheet cassette is configured to move above the accommodatingportion and with respect to the sheet feeder from a first position to asecond position and from the second position to the first position, andthe sheet feeder selectively feeds the first plurality of sheets and thesecond plurality of sheets. In this sheet feed device, different typesof sheets or different sized sheets, or both, may be selectively fed.

According to another embodiment of the present invention, theabove-described sheet feed device may be incorporated into an imagerecording apparatus. The image recording apparatus comprises a housing,a recording unit that records an image on a sheet, and a sheet feed paththrough which the sheet is fed to the recording unit. The recordingunit, the sheet feed path, and the sheet feeder of the sheet feed deviceare accommodated in the housing. The first and second sheet cassettes ofthe sheet feed device are disposed at a lower position than therecording unit, and may be moved inward and outward with respect to thehousing.

In this image recording apparatus, sheets may be readily reloaded in thefirst and the second sheet cassettes by moving the first and the secondsheet cassettes outward with respect to the housing.

Other advantages of the present invention will be apparent to persons ofordinary skill in the art in view of the following detailed descriptionof the invention and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theneeds satisfied thereby, reference now is made to the followingdescriptions taken in connection with the accompanying drawings.

FIG. 1 is a perspective view of an image recording apparatus.

FIG. 2 is a side cross-sectional view of the image recording apparatus.

FIG. 3 is a perspective view of a recording device exposed when an imagereading device is removed.

FIG. 4 is a perspective view of a sheet feed device according to a firstembodiment of the present invention, in which a second sheet cassette isset at a sheet feed position on a first sheet cassette.

FIG. 5 is a perspective view of the sheet feed device in which thesecond sheet cassette is moved back to a non-sheet-feed position.

FIG. 6A is a cross-sectional view of the sheet feed device taken alongline VIA-VIA of FIG. 4.

FIG. 6B is a cross-sectional view of the sheet feed device taken alongline VIB-VIB of FIG. 5.

FIG. 7A is a left side view of the sheet feed device of FIG. 4.

FIG. 7B is a left side view of the sheet feed device in which anupstream portion, as seen in the sheet feed direction, of the secondsheet cassette in the sheet feed position is raised.

FIG. 8A is a left side view of the sheet feed device of FIG. 5.

FIG. 8B is a left side view of the sheet feed device in which anupstream portion, as seen in the sheet feed direction, of the secondsheet cassette in the non-sheet-feed position is raised.

FIG. 9A is a plan view showing a state where a slant (rear corner) guideis used in the second sheet cassette.

FIG. 9B is a plan view showing another state where the slant guide isused in the second sheet cassette.

FIG. 10A is a plan view showing a state where a rear guide and a movableside guide are used in the second sheet cassette.

FIG. 10B is a plan view showing another state where the rear guide andthe movable side guide are used in the second sheet cassette.

FIG. 11 is a bottom view of a carriage showing sensors.

FIG. 12 is a perspective view showing an inclined separation plate ofthe first sheet cassette.

FIG. 13 is a sectional view of the inclined separation plate taken alongline XIII-XIII of FIG. 9A.

FIG. 14A is a side view of a cam follower of a sheet feeder and a cam ofthe second sheet cassette in a state shown in FIG. 4.

FIG. 14B is a side view of the cam follower of the sheet feeder and thecam of the second sheet cassette in a state shown in FIG. 5.

FIG. 14C is a side view of the cam follower of the sheet feeder and thecam of the second sheet cassette when the second sheet cassette isbetween the sheet feed position and the non-sheet-feed position.

FIG. 15 is a perspective view of modified first and second sheetcassettes, where the second sheet cassette having an auxiliary inclinedseparation plate is set at the sheet feed position on the first sheetcassette.

FIG. 16 is a perspective view of the modified first and second sheetcassettes, where the second sheet cassette is moved back to thenon-sheet-feed position on the first sheet cassette.

FIG. 17A is a cross-sectional view of the first and second sheetcassettes taken along line XVIIA-XVIIA of FIG. 15.

FIG. 17B is a cross-sectional view of the first and second sheetcassettes taken along line XVIIB-XVIIB of FIG. 16.

FIG. 18 is a perspective view of modified first and second sheetcassettes, where the piggyback-type second sheet cassette is set at thesheet feed position on the first sheet cassette.

FIG. 19 is a perspective view of the modified first and second sheetcassettes, where the second sheet cassette is moved back to thenon-sheet-feed position on the first sheet cassette.

FIG. 20A is a cross-sectional view of the first and second sheetcassettes taken along line XXA of FIG. 18.

FIG. 20B is a cross-sectional view of the first and second sheetcassettes taken along line XXB-XXB of FIG. 19.

FIG. 21 is a perspective view of a sheet feed device according to asecond embodiment of the present invention in which a second sheetcassette is set at a sheet feed position on a first sheet cassette.

FIG. 22 is a perspective view of the sheet feed device according to thesecond embodiment as viewed from a different direction from in FIG. 21.

FIG. 23 is a plan view of the sheet feed device according to the secondembodiment.

FIG. 24 is a cross-sectional view of the sheet feed device taken alongline XXIV-XXIV of FIG. 23.

FIG. 25 is perspective view of a sheet feed device according to a thirdembodiment of the invention in which a second sheet cassette is set at asheet feed position on a first sheet cassette.

FIG. 26 is a perspective view of the sheet feed device according to thethird embodiment of the present invention, as viewed from a differentdirection from in FIG. 25.

FIG. 27 is a plan view of the sheet feed device according to the thirdembodiment.

FIG. 28 is a cross-sectional view of the sheet feed device taken alongline XXVIII-XXVIII of FIG. 27.

FIG. 29A is a cross-sectional view of the sheet feed device taken alongline XXIXA-XXIXA of FIG. 27.

FIG. 29B is a cross-sectional view of the sheet feed device taken alongline XXIXB-XXIXB of FIG. 27.

FIG. 29C is a side view of a first sheet feeder according to the thirdembodiment in a state where the second sheet cassette is moved back to anon-sheet-feed position.

FIG. 29D is a side view of the first sheet feeder and a second sheetfeeder according to the third embodiment, in a state where the secondsheet cassette is moved back to the non-sheet-feed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention may be understood byreferring to FIGS. 1-29D, like numerals being used for likecorresponding parts in the various drawings.

FIG. 1 shows an image recording apparatus 1 according to an embodimentof the present invention. Image recording apparatus 1 may be amulti-function device (MFD) that has printing, copying, scanning, andfacsimile functions. As shown in FIGS. 1 and 2, image recordingapparatus 1 may have a housing 2 as a main body of the apparatus.Housing 2 may be formed by injection-molding of a synthetic resinmaterial. A first sheet cassette 3, which can be inserted from anopening 2 a at the front of housing 2 (on the left in FIG. 2), may bedisposed at the bottom of housing 2. A second sheet cassette 30 may bemovably connected to or placed on an upper surface of first sheetcassette 3. Hereinafter, a side on which opening 2 a is located isreferred to as a “front” side of image recording apparatus 1, and a sideopposite from opening 2 a is referred to as a “rear” side of imagerecording apparatus 1.

On an upper portion of housing 2, an image reading device 12 may bedisposed for reading a document during the copying and facsimileoperation of image recording apparatus 1. Image reading device 12 may bearranged to be pivotable upward and downward about one end of housing 2via hinges (not shown). A document cover member 13 may be connected atits rear end to a rear end of image reading device 12 via hinges 12 a soas to be pivotable upward and downward about hinges 12 a.

An operation panel 14 provided with various operation buttons and aliquid crystal display may be disposed on an upper side of housing 2, ona front side of image reading device 12. A glass plate 16 may beprovided or on an upper surface of image reading device 12. A documentmay be placed on glass plate 16 by opening document cover member 13 in aupward direction. Below glass plate 16, an image scanning device (CIS:Contact Image Sensor) for reading an image on the document may beprovided so as to be reciprocally movable along a guide shaft 17 a thatextends in a direction perpendicular to a sheet plane of FIG. 2 (a mainscanning direction or a Y-axis direction in FIGS. 1, 2 and 3).

Below image reading device 12 and operation panel 14, a recording unit7, a sheet discharge portion 10, and an ink storage portion 15 disposedon one side of sheet discharge portion 10 may be located within aprojected area of image reading device 1 and operation panel 14.

As shown in FIGS. 2 and 3, recording unit 7 may be defined by a mainframe 21 having an upwardly open box structure, and a first guide member22 and a second guide member 23 that comprise elongate plates supportedby side plates of main frame 21 and extend in the Y-axis direction (mainscanning direction). A carriage 5, on which a recording head 4 ofrecording unit 7 may be mounted may be supported by first guide member22 located upstream of carriage 5 as seen in a sheet discharge direction(indicated by arrow B) the second guide member 23 located downstream ofcarriage 5 so as to be slidably movable on first guide member 22 andsecond guide member 23. Thus, carriage 5 may be reciprocally movable inthe Y-axis direction.

In order to reciprocally move carriage 5, a timing belt 23 may bedisposed on an upper surface of the second guide member 23 as seen inthe sheet discharge direction. Timing belt 24 extends in the mainscanning direction (Y-axis direction) and is wound around pulleys. Acarriage motor 25 (FIG. 3) to drive timing belt 24 may be fixed to alower surface of second guide member 23. Carriage motor 25 may be a DCmotor, a stepping motor, or the like. Second guide member 23 may beprovided with an encoder strip 47 that extends in the main scanningdirection and detects the position of carriage 5 in the Y-axis direction(main scanning direction). Encoder strip 47 may be belt-shaped, and adetecting surface of encoder strip 47 may be formed with slits atregular intervals in the Y-axis direction and may be disposed along avertical direction.

A platen 26 may have a flat shape and may extend in the Y-axis directionso as to face an underside of recording head 4 on carriage 5. Platen 26may be fixed above a bottom plate 21 b of main frame 21 between firstguide member 22 and second guide member 23.

As shown in FIGS. 2 and 3, a partition plate 29, e.g., a plate made of asynthetic resin, may be formed integrally with housing 2 so as to extendfrom a lower surface of second guide member 23 to opening 2 a (used alsoas a sheet-discharge opening) at the front end of housing 2 to coversheet discharge portion 10.

Ink storage portion 15 may be open upward of housing 2, and mayaccommodate, for full-color recording, ink cartridges 19 (black, cyan,magenta, and yellow ink cartridges 19 a-19 d in FIG. 3), which may bedetachably attached from above to ink storage portion 15 in a row alongthe X-axis direction. Each of ink cartridges 19 may have a rectangularbox shape and may have a relatively small area (as seen in plan view)and a relatively large height.

Ink may be supplied from ink cartridges 19 a-19 d to inkjet-typerecording head 4 though a plurality of ink tubes 20, e.g., (four inktubes). When more than four ink colors are used e.g., 6 to 8 ink colors,ink storage portion 15 may be designed to accommodate ink cartridgescorresponding in number to the number of ink colors, and ink tubes 20may be increased in number corresponding to the number of inkcartridges.

As shown in FIG. 3, root portions of the plurality of ink tubes 20 maybe connected to one end 15 a of ink storage portion 15, and may extendfrom one side (left side in FIG. 3) to the other side (right side inFIG. 3) along the Y-axis direction. The root portions of ink tubes 20may be arranged horizontally in a row along an upper surface ofpartition plate 29, which may be substantially horizontal. At least oneportion, e.g., intermediate portions, of ink tubes 20 may be supportedby the upper surface of partition plate 29.

Then, ink tubes 20 may be twisted, e.g., at their middle portions, toextend along a vertical side surface of a laterally elongated uprightpartition plate 32 of partition plate 29, and may be secured, e.g., heldor sandwiched, in a row vertically between the vertical side surface ofupright partition plate 32 and a holder 33, which may be made of asynthetic resin, into a vertical plate and fixed with a screw or thelike to face the vertical side surface. Holder 33 and upright partitionplate 32 serve as an intermediate holder to secure (hold) ink tubes 20.

An ink receiver (not shown) may be disposed at one side of recordingunit 7 at the outside of the width (shorter side) of a sheet P to befed, and a maintenance unit (not shown) may be disposed at the otherside thereof. The ink receiver receives the ink ejected from recordinghead 4 when ink ejection is performed periodically to prevent the nozzlefrom clogging during recording operation at a flashing position providedto face the ink receiver. The maintenance unit performs maintenance ofrecording head 4 when carriage 5 is at a stand-by position. Themaintenance unit covers the nozzle surface of recording head 4 from thebottom with its cap portion (not shown) and selectively sucks each colorink or eliminates air bubbles from a buffer tank (not shown) aboverecording head 4. When carriage 5 moves sideways toward the maintenanceunit, a cleaner (wiper blade) wipes the nozzle surface.

As shown in FIG. 3, according to one embodiment of the presentinvention, a flexible flat cable 40, which transfers command signals forselective ink ejection from the nozzles of recording head 4 from acontrol portion provided in housing 2 to recording head 4, may bearranged substantially in parallel with the extending direction of inktubes 20, at an area where ink tubes 20 pass when carriage 5 movesreciprocally in the Y-axis direction, i.e., at a movable or non-bundledarea of ink tubes 20.

Intermediate bent portions of ink tubes 20 and an intermediate bentportion of flexible flat cable 40 may protrude in opposite directionswith respect to the reciprocally moving direction of carriage 4. Thisarrangement allows ink tubes 20 and flexible flat cable 40 to be locatedat substantially the same height in the vertical direction, that is, ona substantially same horizontal plane. Thus, image recording apparatus 1may be relatively thin.

As shown in FIG. 2, a pair of register rollers (transport rollers) maybe disposed upstream of the platen 26 as seen in the sheet dischargedirection to feed the sheet P to the underside of recording head 4, anda discharge roller 28 may be disposed downstream of platen 26 todischarge the printed sheet P to sheet discharge portion 10.

The structure of a sheet feed device 100 according to a first embodimentof the present invention will now be described. In this embodiment,sheet feed device 100 comprises a first sheet cassette 3 and a secondsheet cassette 30. First sheet cassette 3 has an accommodating portion 3b configured to accommodate a stack of sheets P, and sheets P inaccommodating portion 3 b may be fed in a sheet feed direction(indicated by arrow A) toward recording unit 7 one by one by a sheetfeeder 6. Second sheet cassette 30 may be disposed above accommodatingportion 3 b and may be movable back and forth with respect to sheetfeeder 6. Second sheet cassette 30 may be configured to accommodate astack of sheets P1 that are different in size from the sheets Paccommodated in first sheet cassette 3, e.g., sheets P1 may besmaller-sized sheets, such as postcards and L-sized photograph sheets.The sheets P1 in second sheet cassette 30 may be fed in the samedirection as the feed direction of the sheets P. When second sheetcassette 30 is moved back (pulled back) with respect to first sheetcassette 3 in a direction opposite to the sheet feed direction, that is,in the sheet discharge direction, an upstream end of second sheetcassette 30 is positioned behind (upstream of) an upstream end of firstsheet cassette 3 as seen in the sheet feed direction.

As shown in FIGS. 2, 4 and 5, a drive shaft 6 d made of a syntheticresin may be rotatably supported by shaft holes formed in a side plate(not shown) and a pair of shaft supporting plates (not shown) of mainframe 21. Drive shaft 6 d may be inserted into the shaft holes, suchthat an end of drive shaft 6 d projects sideways from a base portion ofa sheet feed arm 6 a. When drive shaft 6 d is driven to rotate, sheetfeed roller 6 b may rotate in a predetermined direction(counterclockwise direction in FIG. 2) via a gear transmission mechanism6 c provided in sheet feed arm 6 a. Sheet feed roller 6 b may be urgeddownward by an urging member, e.g., a torsion spring (not shown).

First sheet cassette 3 may be configured to accommodate a stack oflarger cut sheets P, such as A4-sized sheets, letter-sized sheets, andlegal-sized sheets, such that a shorter side of the cut sheet P extendsin the Y-axis direction (main scanning direction). In this embodiment ofthe present invention, the maximum capacity of the accommodating portion3 b of the first sheet cassette 3 may be about 100 sheets of plainpaper, or a stack having a height (H1) of about 10 mm. As shown in FIG.1, an auxiliary support member 3 a may be provided movably in the sheetfeed direction (sub scanning direction or X-axis direction) in a recess3 d at an upstream end of first sheet cassette 3 as seen in the sheetfeed direction (at a front side of housing 2) to support the trailingedges of longer sheets, such as legal-sized sheets. As shown in FIGS. 1,4, 9A, and 9B, a trapezoidal hole may be formed near the upstream end ofauxiliary support member 3 a to provide a grip 3 f with which firstsheet cassette 3 can be readily inserted and removed through opening 2 aof housing 2.

A main inclined separation plate 8 for separating one sheet from theothers may be disposed at a downstream end (on the right side in FIG. 2)of first sheet cassette 3 as seen in the sheet feed direction. Thesheets P stacked in first sheet cassette 3 are separated one by one bythe sheet feed roller 6 b and an elastic separation pad 8 a (formed by ametal spring in this embodiment) provided on an inner surface and at thecenter in the width direction (Y-axis direction) of inclined separationplate 8. The separated sheet P is fed, via a sheet feed path member 9that defines a U-turn path (sheet feed path) 9 a extending upward, torecording unit 7 located at a higher position than first sheet cassette3. Then, the sheet P recorded thereon by recording unit 7 may bedischarged to discharge portion 10 communicating with opening 2 a, withthe recorded surface facing upward.

As shown in FIGS. 4 and 9, main inclined separation plate 8 may have acurved surface such that, as seen in a direction perpendicular to thesheet feed direction, a portion near elastic separation pad 8 a in theform of a sawtooth is closer to the widthwise center of a leading edgeof the sheet P and is more remote from the widthwise ends of the leadingedge of the sheet P. Thus, before the leading edge of the sheet P comesinto contact with main inclined separation plate 8 at the widthwiseends, the leading edge of the sheet P comes in sliding contact withelastic separation pad 8 a at the widthwise center, and thereby thesheet P is reliably separated. As shown in FIGS. 4 and 5, freelyrotatable rollers 28 may be provided adjacent to an upper end of maininclined separation plate 8 on both sides of elastic separation pad 8 ato guide the sheet P smoothly to sheet feed path member 9. Main inclinedseparation plate 8 may be detachably attached to the downstream end offirst sheet cassette 3 as seen in the sheet feed direction.

A pair of left and right side guides 34 a, 34 b, respectively, may beprovided in accommodating portion 3 b of first sheet cassette 3, as aguide unit, and may be movable in a direction perpendicular to the sheetfeed direction to position and guide the sheet side edges in parallelwith the sheet feed direction. The pair of side guides 34 a, 34 b may beslidable, such that the distance therebetween is widened or narrowed.Racks (not shown) connected to the bottoms of the pair of side guides 34a, 34 b, respectively, may be engaged with a pinion gear located at acenter line of the width (in a direction perpendicular to the sheet feeddirection) of the bottom plate of first sheet cassette 1. Thus, thesheets P are centered in first sheet cassette 3, that is, the widthwisecenter line of the sheets P corresponds with the widthwise center lineof first sheet cassettes P. At least one of the side guides 34 a may beprovided with a handle 38 (FIGS. 4 and 5) that is engaged with and heldat a rack-shaped engaging portion 37 (FIGS. 9A and 9B) formed on anupper surface of first sheet cassette 3.

Second sheet cassette 30 according to the first embodiment of thepresent invention may comprise a bottom plate 30 a provided on adownstream side, and a sheet receiver 30 b formed integrally with thebottom plate 30 a and provided on an upstream side as seen in the sheetfeed direction. The bottom plate 30 a may have a substantiallyrectangular shape as seen in plan view, and holds, as a holding portion,a stack of sheets. On bottom plate (holding portion) 30 a, smallersheets P than those sheets stacked in first sheet cassette 3, such aspostcards and L-sized photograph sheets, may be stacked. Moreover, notonly may sheets having a different size be employed, but also sheets ofa different type than those sheets stacked in the first sheet cassette 3may be employed. For example, sheets exclusively for inkjet printing andcalendared sheets for photograph quality printing may be stacked on thebottom plate (holding portion) 30 a.

The width W2 of bottom plate 30 a may be smaller than the width W1 offirst sheet cassette 3, and bottom plate 30 a may be placed at a centralportion in the width direction of first sheet cassette 3. Cutouts 70 maybe provided in bottom plate 30 a, such that one end of bottom plate 30 ais narrower in width. This structure allows the user to readily accesshandle 38 of side guide 34 b without removing second sheet cassette 30,and facilitates widthwise positioning of the sheets P in first sheetcassette 3. Sheet receiver 30 b may be formed integrally with bottomplate 30 a and may have a continuously wide width from bottom plate 30a, which is substantially equal to width of the first sheet cassette 30.As shown in FIGS. 4, 5, 6A, 6B, 9A, and 9B, sheet receiver 30 b may beformed with a cutout 39 open toward the front of image recordingapparatus 1 to facilitate allowing the user to pinch the edge of thesheet P (P1) with their fingers.

Because sheet receiver 30 b is connected to bottom plate 30 a via astep, such that sheet receiver 30 b is elevated higher than bottom plate30 a, the sheets P (P1) recorded thereon and discharged from recordingunit 7 are likely to pass over the blank sheets P (P1) stacked on bottomplate 30 a and reach sheet receiver 30 b.

Second sheet cassette 30 may be connected to first sheet cassette 3 andmay be movable back and forth along the sheet feed direction andpivotable upward at its upstream end as seen in the sheet feed,direction. More specifically, as shown in FIGS. 4, 5, 7A, 7B, 8A, and8B, guide holes 35 elongated in the sheet feed direction may be formedin the right and left side plates 3 c of first sheet cassette 3 thatextend in parallel with the sheet feed direction. Round shafts 36projecting integrally from both sides of a downstream portion (forexample, bottom plate 30 a) of second sheet cassette 30 may be fittedinto the respective guide holes 35, such that round shafts 36 aremovable in the sheet feed direction and second sheet cassette 30 ispivotable about round shafts 36. The diameter of each of guide holes 35may be formed, at its downstream end 35 a as seen in the sheet feeddirection, to be relatively large and upwardly inclined. Accordingly, byinclining round shafts 36 with respect to the Y-axis direction, roundshafts 36 readily may be inserted into guide holes 35.

As shown in FIGS. 5, 6A, 6B, 9A, and 9B, a pair of engaging pieces 31,which may have an upwardly hooked shape, may be formed at a downstreamend of bottom plate (holding portion) 30 a provided on the downstreamside of second sheet cassette 30 as seen in the sheet feed direction.When second sheet cassette 30 is pushed to the sheet feed position, thepair of engaging pieces 31 respectively engage a pair of positioningholes 8 b (FIGS. 9A, 9B, 10A, and 12) formed in main inclined separationpanel 8 of first sheet cassette 3. As shown in FIG. 13, engaging piece31 engages, at a recess 31 a formed in its lower surface, a lower edgeof positioning hole 8 b, thereby holding second sheet cassette 3 in astate pushed to the sheet feed position not to be displaced in verticaland widthwise directions. Engaging pieces 31 and positioning holes 8 bmay be provided on both sides of elastic separation pad 8 a atappropriate intervals in the longitudinal direction of main inclinedseparation panel 8, that is, in the sheet width direction. Thus, whensecond sheet cassette 30 is set at the sheet feed position with respectto first sheet cassette 3, second sheet cassette 30 may be preventedfrom being displaced in the vertical direction or in the sheet widthdirection and from being inclined with respect to the verticaldirection. Second sheet cassette 30 may be kept at the sheet feedposition to be parallel with the vertical direction and the sheet feeddirection, and thus, separation and feeding of the sheets P1 isperformed reliably in a stable manner.

Right and left side plates 30 c of second sheet cassette 30 may beformed integrally with bottom plate 30 a to extend along the sheet feeddirection. A guide unit for positioning the sheets P1 to be parallelwith the sheet feed direction may be provided in an intermediate portionon an upper surface of bottom plate 30 a. As shown in FIGS. 4-9B, theguide unit comprises, a slant guide 41 that contacts a rear corner ofeach sheet P1 and one of side plates 30 c, as a fixed side guide thatguides a side edge of each sheet P1. Slant guide 41 comprises a rearplate 41 a that contacts the trailing edge of each sheet P1 placed withits one side edge in contact with the one of side plates 30 c, and aside plate 41 b that extends in parallel with side plates 30 c andcontacts the other side edge of each sheet P1. Slant guide 41 may befitted into a guide groove 42 formed slantingly in the bottom plate 30a, so as to be movable along guide groove 42.

As shown in FIG. 9A, the slanting degree of guide groove 42 is set suchthat when the sheet P1 is an L-sized sheet, the sheet P1 contacts at itstrailing edge with rear plate 41 a, and at the same time, at its sideedge with side plate 41 b. When the sheet P1 is a postcard, which isdifferent in the ratio of a longer side and a shorter side from anL-sized sheet, as shown in FIG. 9B, the sheet P1 contacts either at itstrailing edge with rear plate 41 a or at its side edge with side plate41 b. The slanting degree of guide groove 42 may be set differently fromin FIGS. 9A and 9B, such that when the sheet P1 is a postcard, the sheetP1 contacts at its trailing edge with rear plate 41 a, and at the sametime, at its side edge with side plate 41 b. In FIGS. 9A and 9B, sideguides 34 a, 34 b of first sheet cassette 3 are omitted.

When the auxiliary support member 3 a of first sheet cassette 3 isaccommodated in accommodating portion 3 b and second sheet cassette 30is pushed to the downstream end of first sheet cassette 3 as seen in thesheet feed direction, the length in the X-axis direction of first sheetcassette 3 and second sheet cassette 30 is substantially equal to thelength in the X-axis direction of image reading device 12 and operationpanel 14. Image recording apparatus 1 may be a substantially rectangularparallelepiped shape and may be substantially square as seen in planview. Thus, image recording apparatus 1 easily may be packed forshipment, and a packing box including image recording apparatus 1 may becompact.

First sheet cassette 3 and second sheet cassette 30 may be inserted intoand removed from a bottom portion of housing 2 unitarily in a statewhere second sheet cassette 30 is pushed into the downstream end offirst sheet cassette 3 as seen in the sheet feed direction. Uponinsertion and removal of first sheet cassette 3 and second sheetcassette 3, sheet feed arm 6 a may be moved up and down automatically.Such a structure will now be described in detail. As shown in FIGS. 4and 5, a cam follower 43 shaped like a flat plate projects integrallyfrom sheet feed arm 6 a of a synthetic resin in a direction parallelwith drive shaft 6 and extends over an auxiliary cam 44 formed on anupper surface of one of side plates 30 c of second sheet cassette 30.

As shown in FIGS. 14A, 14B and 14C, auxiliary cam 44 comprises a firstguide 44 a that is inclined so as to be lower on the most downstreamside of second sheet cassette 30 as seen in the sheet feed direction andgradually higher toward the upstream side thereof, a second guide 44 bconnected to first guide 44 a and having a substantially uniform height,and a third guide 44 c connected to second guide 44 b and recessed intoa substantially V shape.

When first cassette 3 and second sheet cassette 30 are insertedunitarily from opening 2 a at the front of housing 2, and cam follower43 contacts at its lower surface with first guide 44 a of auxiliary cam44 provided on a side closer to main inclined separation plate 8, camfollower 43 may be raised as second sheet cassette 30 is moved forth(inward), and sheet feed arm 6 a and sheet feed roller 6 a may bepivoted upward together with cam follower 43, and sheet feed roller 6 band sheet feed arm 6 a pass over main inclined separation panel 8.

When sheet feed arm 6 a and sheet feed roller 6 b are raised by camfollower 43 in contact with second guide 44 b, sheet feed arm 6 a andsheet feed roller 6 b may retract through an opening 21 c provided inbottom plate 21 b of main frame 21 into a space within main frame 21. Atthis time, cam follower 43 may come in contact with or may be drawncloser to a lower surface of bottom plate 21 b. This structure allowssheet feed arm 6 a and sheet feed roller 6 b to pivot vertically withoutincreasing the height of a space defined between bottom plate 21 b andsecond sheet cassette 30. Accordingly, the height between first sheetcassette 3 and bottom plate 21 b of the main frame 21 may be reduced,and image recording apparatus 1 may be relatively short in overallheight.

When cam follower 43 reaches a descending portion of third guide 44 cafter passing over second guide 44 b, sheet feed arm 6 a, which is urgeddownward, and sheet feed roller 6 b may be pivoted downward. Then, asshown in FIG. 14A, sheet feed roller 6 b may come into contact with theuppermost one of the sheets P1 stacked on bottom plate 30 a.

When second sheet cassette 30 is moved back (outward) in a state wherefirst sheet cassette 3 is set at a fully pushed position (sheet feedposition) in housing 2, cam follower 43 slides over third guide 44 c,second guide 44 b (FIG. 14C), and first guide 44 a in this order, andfinally comes off side plate 30 c of second sheet cassette 3. As shownin FIG. 14B, when second sheet cassette 3 is at a position moved backfrom sheet feed roller 6 b (at a non-sheet-feed position), sheet feedroller 6 b is allowed to contact the bottom (the uppermost one of thesheets P) of first sheet cassette 3 and perform sheet feed operation. Onthe other hand, when second sheet cassette 30 is moved forth to thesheet feed poison from the non-sheet-feed position in a state wherefirst sheet cassette 3 is set at the sheet feed position in housing 2,cam follower 43 slides over first guide 44 a, second guide 44 b (FIG.14C), and third guide 44 c in this order, and sheet feed roller 6 b isallowed to contact the uppermost one of the sheets P1 in second sheetcassette 30.

As described above, cam follower 43 provided at sheet feeder 6cooperates with auxiliary cam 44 provided at second sheet cassette 30 tovertically pivot sheet feed roller 6 a temporarily as second sheetcassette 30 is moved back and forth on first sheet cassette 3 in housing2. Also, by the cooperation between cam follower 43 and auxiliary cam44, sheet feed roller 6 a is moved up and down automatically not tocollide with main inclined separation plate 8 when first sheet cassette3 is inserted to and removed from housing 2 unitarily with second sheetcassette 30 that is fully pushed into first sheet cassette 3. Thus,handling of first sheet cassette 3 and second sheet cassette 30 is madeeasy.

When second sheet cassette 30 stacked with smaller-sized sheets P1 ispushed to the sheet feed position near the downstream end of first sheetcassette 3 as seen in the sheet feed direction, in a state wherelarger-sized sheets P are stacked in first sheet cassettes 3, sheet feedroller 6 b is allowed to press the uppermost one of the sheets P1 insecond sheet cassette 30. Thus, image recording operation can be carriedout in this state. On the other hand, when second sheet cassette 30stacked with smaller-sized sheets P1 is pulled back to a position whereround shafts 36 reach the upstream ends of guide holes 35 as seen in thesheet feed direction, second sheet cassette 3 is not detached from firstsheet cassette 3, and the sheets P1 are prevented from getting out ofposition by slant guide 41. In this case, image recording operation canbe carried out immediately by feeding, the sheets P in first sheetcassette 3 with sheet feed roller 6 b. Because elastic separation pad 8a of main inclined separation plate 8 is located within the width ofbottom plate 30 a of second sheet cassette 30, a single sheet feedroller 6 b and a single separation plate 8 can be commonly used forseparation and feeding of the sheets P (P1) stacked in first sheetcassette 3 and second sheet cassette 30.

First sheet cassette 3 may be replenished with sheets P by lifting theupstream end of the second sheet cassette 30 as shown in FIG. 7B in astate where second sheet cassette 30 is pushed with respect to firstsheet cassette 3 (to the sheet feed position) as shown in FIG. 7A, or bylifting the upstream end of second sheet cassette 30 as shown in FIG. 8Bin a state where second sheet cassette 30 is pulled back with respect tofirst sheet cassette 3 (to the non-sheet-feed position) as shown in FIG.8A. In either case, second sheet cassette 30 may be pivoted upward aboutround shafts 36 to provide a larger vertical space at the upstream endof first sheet cassette 3, thereby facilitating loading sheets P infirst sheet cassette 3.

Accommodating portion 3 b of first sheet cassette 3 may be inclineddownward toward main inclined separation plate 8, that is, toward thesheet feed direction, and accommodating portion 3 b may open outwardthrough opening 3 a of housing 2. Sheet feed arm 6 a of sheet feeder 6may be configured to move tiltably. Thus, the sheets P stacked inaccommodating portion 3 b of first sheet cassette 3 are not displacedtoward the upstream side as seen in the sheet feed direction, and anadditional guide member to contact the trailing edges of the sheets P isnot needed. Sheets P can be loaded to first sheet cassette 3 from itsupstream side without lifting the upstream end of second sheet cassette30.

Sheet receiver 30 b may be formed continuously from bottom plate(holding portion) 30 a of second sheet cassette 30. When image recordingis performed with second sheet cassette 30 set at the sheet feedposition as shown in FIG. 6A, smaller-sized sheets P1 in second sheetcassette 30 are fed to recording unit 7, and the sheets P1 recordedthereon are received by sheet receiver 30 b without being mixed with theblank sheets P1. Also, when image recording is performed forlarger-sized sheets P as shown in FIG. 6B, the sheets P recorded thereonare received by sheet receiver 30 b of second sheet cassette 30 pulledback to the non-sheet-feed position, reliably without projecting fromsheet receiver 30 b. In these cases, because sheet receiver 30 b isformed with a cutout 39 open toward the front of housing 2, the user caninsert fingers into cutout 39 and readily take out the sheets P (P1).

FIGS. 10A and 10B show a modification of guide unit 41 of the firstembodiment, of the present invention which guides the side edges of thesheets P1 on bottom plate 30 a of second sheet cassette 30 to beparallel with the sheet feed direction. In this modification, the guideunit comprises one of side plates 30 c as a fixed side guide that guidesone side edge of each sheet P1, a movable side guide 45 a that extendsin parallel with the one of side plates 30 and moves towards and fromone of the side plates 30 c, and a rear guide 45 b that is movable alongthe sheet feed direction to contact the trailing edge of each sheet P1.Movable side guide 45 a and rear guide 45 b may be mounted on bottomplate 30 a of second sheet cassette 30 so as to be movable linearly.With this structure, even when the ratio of a shorter side and a longerside of the sheet P1 used varies, the sheet P1 can be positionedreliably. In addition, smaller-sized sheets P1 are placed at theirsmaller side edges opposed to elastic separation pad 8 a of first sheetcassette 3, and thus the sheets P1 may be separated one by one byelastic separation pad 8 a in cooperation with sheet feed roller 6 b.

As shown in FIG. 11, image recording apparatus 1 may comprise a mediasensor 49 and a cassette sensor 50 that are provided on an underside ofcarriage 5. Media sensor 49 detects the width of the sheet P (P1) fed tothe recording unit 7, and cassette sensor 50 detects whether secondsheet cassette 30 is set at the sheet feed position. A non-contact typephotosensitive sensor, such as an infrared sensor, may be used for bothmedia sensor 49 and cassette sensor 50. A detection hole (not shown) maybe provided in the platen intermediate in the Y-axis direction, so thatcassette sensor 50 can detect bottom plate 30 a through the detectionhole only when second sheet cassette 30 is set at the sheet feedposition. When carriage 5 moves in the Y-axis direction, media sensor 49detects the width of the leading edge of the sheet P (P1) that isstopped temporarily after being fed a little bit further from registerrollers 27. When the user commands image recording apparatus 1 to startimage recording by designating the desired type or size of a sheet to beused, and cassette sensor 50 determines from a detected value thatsecond sheet cassette 30 stacked with the designated sheets is not setat (pushed to) the sheet feed position, sheet feed may be prohibited andan error message may be reported to the user. Sheet feed is notpermitted until the user sets second sheet cassette 30 at the sheet feedposition. Similarly, when first sheet cassette 3 is stacked with thedesignated sheets, but second sheet cassette 30 stacked with the sheetsdifferent from the desired sheets is set at the sheet feed position,sheet feed is prohibited and an error message may be reported to theuser. Sheet feed is not permitted until the user sets second sheetcassette 30 at the non-sheet-feed position.

When the carriage 5 moves in the Y-axis direction, media sensor 49detects the width of the leading edge of the sheet P (P1) that isstopped temporarily after being fed a little bit further from registerrollers 27, and an electronic control device (not shown) determines thesize of the sheet P (P1) from a detected value. When the size determineddoes not match the type or size designated by the user, image recordingon the fed sheet P (P1) is prohibited and the blank sheet P (P1) isdischarged to sheet discharge portion 10. Thus, the user does not wastesheets. The setting position of the sheet P (P1) in the Y-axis directionalso may be detected by media sensor 49.

FIGS. 15, 16, 17A, and 17B show a modification of first sheet cassette 3and second sheet cassette 30 of the first embodiment of the presentinvention. A second sheet cassette 130 may comprise an auxiliaryinclined separation plate 51 at a downstream end of a bottom plate 30 aas seen in the sheet feed direction. Auxiliary inclined separation plate51 may be provided with an elastic separation pad 51 a that is similarto elastic separation pad 8 a provided for main inclined separationpanel 8. As shown in FIGS. 15 and 16, guide holes 135 for connectingsecond sheet cassette 130 via round shafts 36 to first sheet cassette103 may be formed in side guides 134 a, 134 b of first sheet cassette103. As shown in FIGS. 15 and 17A, when second sheet cassette 130 ispushed with respect to the first sheet cassette 103 and set at the sheetfeed position, auxiliary inclined separation plate 51 is locatedadjacent to an inner surface of main inclined separation plate 8. SheetsP1 in second sheet cassette 130 are fed by rotation of a sheet feedroller 6 b and separated one by one at elastic separation pad 51 a ofauxiliary inclined separation plate 51.

The sheets P1 stacked on bottom panel 30 a are close at their leadingedges to the auxiliary inclined separation plate 51. When second sheetcassette 130 is moved back and forth, auxiliary inclined separationplate 51 cooperates with guide unit 41 to keep the sheets P1 inposition. Accordingly, switching between first sheet cassette 103 andsecond sheet cassette 130 may be performed smoothly.

FIGS. 18, 19, 20A, 20B show another modification of first sheet cassette3 and second sheet cassette 30 of the first embodiment of the presentinvention. A second sheet cassette 230 may be placed on a first sheetcassette 203. Second sheet cassette 230 may comprise a bottom plate 230a, as a sheet holding portion, and a sheet receiver 230 b that has thesame width as that of first sheet cassette 3, and second sheet cassette230 may be placed on right and left side plates 3 c of first sheetcassette 203. Second sheet cassette 230 may be formed with cutouts 52 a,52 b to allow the user to operate a handle 38 for side guides 34 a, 34 beven when second sheet cassette 230 is set on first sheet cassette 203either at a pushed or pulled position.

As shown in FIGS. 18, 19, 20A, and 20B, sheet receiver 230 b may beformed with a hole-shaped cutout 54 at its downstream end as seen in thesheet discharge direction. The user can pull second sheet cassette 230outward through opening 2 a by putting their fingers in cutout 54 andreadily take out the recorded sheets P piled on sheet receiver 30 b.

In this modification of the present invention, because second sheetcassette 230 merely is placed on first sheet cassette 203, second sheetcassette 230 is likely to be displaced in the right-left direction(sheet width direction). To prevent such a displacement, with bottomplate 230 a is provided, at its downstream end as seen in the sheet feeddirection, engaging pieces 231, as shown in FIG. 19. Engaging pieces 231engage positioning holes (not shown) in main inclined separation plate 8when second sheet cassette 230 is moved forth to be set at the sheetfeed position. Second sheet cassette 230 may comprise right and leftguides 53, as a guide unit, that move in parallel with each other suchthat the distance therebetween is widened or narrowed to position andguide the side edges of sheets P1 to be parallel with the sheet feeddirection.

Also, in this modification, of the present invention feeding of sheetsof one size or the other can be readily switched by moving back andforth second sheet cassette 230 to the non-sheet-feed position or thesheet feed position, in a state where sheets P are stacked in firstsheet cassette 203 and sheets P1 different in size from the sheets P arestacked in second sheet cassette 230.

FIGS. 21-24 show a sheet feed device 101 according to a secondembodiment of the present invention. In this embodiment, a sheet feedroller 6 b of a sheet feeder 306 is moved up and down corresponding tothe back and forth movements of a first sheet cassette 303 and a secondsheet cassette 330. A cam follower 43 shaped like a flat plate mayproject integrally, from a sheet feed arm 6 a (drive shaft 6 d isomitted from FIGS. 21-23) and extends towards and over an auxiliary cam44 and a main cam 55. Auxiliary cam 44 may be formed to have a varyingheight on an upper surface of one of side plates 30 c of second sheetcassettes 30, and main cam 55 may be formed to have a varying height onan upper surface of one of side plate 3 c of first sheet cassette 303.An end 43 a of cam follower 43, which contacts main cam 55, has a lengthL1 in the sheet-feed direction, while cam follower 43, which contactsauxiliary cam 44, has a length L2. L1 may be smaller than L2, as shownin FIG. 22.

Auxiliary cam 44 may be the same as in the first embodiment of thepresent invention (FIGS. 4, 5, 6B, 14A, 14B and 14C), and may comprise afirst guide 44 a that is inclined so as to be lower on the mostdownstream side of second sheet cassette 330 and gradually higher towardthe upstream side thereof as seen in the sheet feed direction, a secondguide 44 b connected to first guide 44 a and having a substantiallyuniform height, and a third guide 44 c connected to second guide 44 band recessed into a substantially V shape.

Main cam 55 may comprise a first guide 55 a that has a substantiallyuniform height from the most downstream side of first sheet cassette 303toward the upstream side thereof as seen in the sheet feed direction,and a second guide 55 b connected to first guide 55 a and shaped like Vhaving a smaller height in the middle. As shown in FIG. 24, second guide55 b and third guide 44 c correspond with each other in position in thesheet feed direction. As shown in FIGS. 21 and 22, a sheet side guideplate 56 may be provided on a bottom plate (holding portion) 30 a ofsecond sheet cassette 330, and may be formed with a recess 56 a at aposition corresponding with third guide 44 c and second guide 55 b, soas not to interfere with the movement of cam follower 43.

A guide hole 35 may be formed in each of side plates 3 c of first sheetcassette 303 to be elongated along the sheet feed direction. A wing 57may be formed on each side of bottom plate 30 a of second sheet cassette330 to extend close to an inner surface of each of side plates 3 c. Asshown in FIGS. 21 and 22, a round shaft 58 projecting from thedownstream end of each of the wings 57 toward, the corresponding sideplate 3 c may be movably fitted into the corresponding guide hole 35.With this structure, second sheet cassette 330 is movable back and forthwith respect to first sheet cassette 303 and is pivotable upward anddownward about round shafts 58.

Two ribs 59 a, 59 b may be formed on an inner surface of each of sideplates 3 c at appropriate intervals in the moving direction of secondsheet cassette 330. A projection 57 a may be integrally formed with eachof the wings 57 to provide a click feel when the user moves second sheetcassette 330 selectively back and forth, so that projections 57 a passbeyond ribs 59 a, 50 b.

First sheet cassette 303 and second sheet cassette 330 may be insertedinto housing 2 unitarily in a state where second sheet cassette 330comprising auxiliary cam 44 is fully pushed or pulled back with respectto first sheet cassette 303 comprising main cam 55. In either case, whenend 43 a of cam follower 43 of sheet feeder 306 passes an end edge ofone of side plates 3 c and rides on first guide 55 a, sheet feed arm 6 ais raised to a substantially horizontal orientation, and sheet feedroller 6 b passes beyond main inclined separation plate 8. After that,when end 43 a approaches the lowest portion of the V-Shape of the secondguide 55 b, sheet feed arm 6 a is pivoted downward, and sheet feedroller 6 b is allowed to selectively contact the uppermost one of thesheets P1 in second sheet cassette 330 or the uppermost one of thesheets P in first sheet cassette 303.

When second sheet cassette 330 is moved forth in a state where firstsheet cassette 303 is set at the sheet feed position in housing 2, camfollower 43 comes into sliding contact with auxiliary cam 44 of secondsheet cassette 330, and sheet feed arm 6 a is pivoted upward and thendownward. Thereby, sheet feed roller 6 b is allowed to contact the uppermost one of the sheets P1 stacked on bottom plate 30 a of second sheetcassette 330. On the other hand, when second sheet cassette 30 is movedback, cam follower 43 comes into sliding contact with auxiliary cam 44,and sheet feed arm 6 a is pivoted upward and then downward. Thus, sheetfeed roller 6 b is allowed to contact the upper most one of the sheets Pin accommodating portion 3 b of first sheet cassette 303 withoutdisplacing the sheets P1 stacked in second sheet cassette 330. Secondsheet cassette 330 may be moved back and forth by gripping a handle 30 dprovided at a downstream end of the sheet receiver 30 b as seen in sheetdischarge direction.

In FIGS. 21-23, side guides of the first sheet cassette 303 are omitted.

As described above, by the cooperation of cam follower 43 and auxiliarycam 44, sheet feed roller 6 a is moved up and down automatically assecond sheet cassette 330 is moved back and forth on first sheetcassette 303 in housing 2. By the cooperation of end 43 a of camfollower 43 and main cam 55, sheet feed roller 6 a is moved up and downautomatically without colliding with main inclined separation plate 8when first sheet cassette 303 is inserted into and removed from housing2 unitarily with second sheet cassette 330. Thus, handling of firstsheet cassette 3 and second sheet cassette 30 is made easy.

FIGS. 25-28 show a sheet feed device 102 according to a third embodimentof the present invention. In this embodiment, a first sheet feeder 306for a first sheet cassette 403 and a second sheet feeder 60 for a secondsheet cassette 430 may be disposed side by side, and first sheet feeder306 and second sheet feeder 60 may be configured to be raised or loweredselectively. When sheets P in first sheet cassette 403 are fed, a sheetfeed roller 6 b of first sheet feeder 306 contacts the uppermost one ofthe sheets P in an accommodating portion 3 b of first sheet cassette403, and a sheet feed roller 60 b of second sheet feeder 60 is held at araised position. On the other hand, when sheets P1 in the second sheetcassette 430 are fed, the second sheet feed roller 60 b of the secondsheet feeder 60 contacts the uppermost one of the sheets P1 on a holdingportion 30 a of second sheet cassette 430, and sheet feed roller 6 b offirst sheet feeder 306 is kept at a raised position.

To be more specific, a main cam 55 may be formed, similarly to that inthe second embodiment, of the present invention on each of side plates 3c of first sheet cassette 403, and an auxiliary cam 44 may be formed,similarly to that in the second embodiment, of the present invention onone side plate 30 c (with which a cam follower 61 to be described latercontacts) to comprise a first guide 44 a, a second guide 44 b, and athird guide 44 c shaped like V. The other side plate 30 c (with which acam follower 43 contacts) may be formed at its upper surface with onlyfirst guide 44 a and second guide 44 b that is substantially horizontaland has a uniform height. In FIGS. 25-27, side guides of the first sheetcassette 403 are omitted.

In FIGS. 25-27, drive shaft 6 d and main inclined separation plate 8 areomitted.

Second sheet feeder 60 is the same, in the basic structure, as firstsheet feeder 306. A drive shaft 60 d and cam follower 61 of second sheetfeeder 60 are parallel with drive shaft 6 d of first sheet feeder 306,but extend in the opposite direction to that of drive shaft 6 d. Thatis, drive shaft 60 d and cam follower 61 extend toward and over the sideplates 3 c, 30 c provided on a side remote from cam follower 43, asshown in FIGS. 25-27.

In this third embodiment of the present invention, as shown in FIGS.25-28, when first sheet cassette 403 and second sheet cassette 430 areinserted unitarily into housing 2 in a state where second sheet cassette430 is pushed to sheet feed position with respect to the first sheetcassette 403, an end 43 a of cam follower 43 of first sheet feeder 306contacts an end edge of one side plate 3 c of first sheet cassette 403and rides on a first guide 55 a. At this time, a sheet feed arm 6 a israised to a substantially horizontal orientation, and sheet feed roller6 b passes beyond a main inclined separation plate 8. Then, anintermediate portion of cam follower 43 is kept in contact with highhorizontal second guide 44 b, and thereby sheet feed arm 6 a of firstsheet feeder 306 is kept at a substantially horizontal orientation, asshown in FIGS. 29A and 29B. Meanwhile, when cam follower 61 of secondsheet feeder 60 contacts an end edge of the other side plate 3 c offirst sheet cassette 403 and rides on a first guide 55 a, sheet feed arm60 a is pivoted upward, and sheet feed roller 60 b is allowed to passover main inclined separation plate 8. Then, cam follower 61 contacts afirst inclined guide 44 a and a horizontal second guide 44 b ofauxiliary cam 44 of the other side plate 3 c. After that, when camfollower 61 reaches the low, V-shaped third guide 44 c (and a V-shapedsecond guide 55 b of first sheet cassette 403), sheet feed arm 60 a ispivoted downward, and sheet feed roller 60 b is allowed to contact theuppermost one of the sheets P1 stacked on bottom plate 30 a of secondsheet cassette 430.

When second sheet cassette 430 is moved to the non-sheet-feed positionin a state where first sheet cassette 403 is set at the sheet feedposition, cam follower 61 of second sheet feeder 60 is raised alongV-shaped third guide 44 c, and slides on high horizontal second guide 44b. After that, cam follower 61 is lowered along the first inclined guide44 a, and finally comes off auxiliary cam 44. At this time, however, anend of cam follower 61 is in contact with high horizontal first guide 55a of first cam 55, and thus sheet feed roller 60 b is kept at such anorientation that its lower surface is away from the uppermost one of thesheets P in accommodating portion 3 b of first sheet cassette 403, asshown in FIG. 29D. At this time, sheet feed roller 6 b of first sheetfeeder 306 is allowed to contact the uppermost one of the sheets P inaccommodating portion 3 b.

As describe above, first sheet feeder 306 and second sheet feeder 60 areshifted selectively to an operating position or a non-operating positionfor sheet feeding as first sheet cassette 403 and second sheet cassette430 are moved unitarily to and from the sheet feed position and assecond sheet cassette 430 is moved on first sheet cassette 403 betweenthe sheet feed position and the non-sheet-feed position. Second sheetcassette 430 may be moved back and forth by gripping a handle 30 d thatis provided at a downstream end of sheet receiver 30 b as seen in thesheet discharge direction.

As shown in FIG. 29A, the height L4 of the sheet feed arm 60 a of thesecond sheet feeder 60 may be smaller than the height L3 of sheet feedarm 6 a of the first sheet feeder 306. The upper surface of the sheet Pin first sheet cassette 403 forms an angle θ1 with a line between thepivot center of sheet feed arm 6 a (axis of drive shaft 6 d) and a pointwhere sheet feed roller 6 b contacts the upper surface of the sheet P.Similarly, the upper surface of the sheet P1 in second sheet cassette430 forms an angle θ2 with a line between the pivot center of sheet feedarm 60 a (axis of drive shaft 60 d) and a point where sheet feed roller60 b contacts the upper surface of the sheet P1. θ1 may be substantiallyequal to θ2, when L4 is smaller than L3, drive shafts 6 d, 60 d are atsubstantially the same height, and second sheet cassette 30 is at aposition higher than first sheet cassette 403. Accordingly, the sheetfeed force of sheet feed roller 6 b may be substantially the same asthat of sheet feed roller 60 b.

According to the first through third embodiments of the presentinvention, as described above, sheet feed device 100, 101, 102 has firstsheet cassette 3, 303, 403 set at the sheet feed position and secondsheet cassette 30, 330 430 disposed movably on first sheet cassette 3,303, 403. The first sheet cassette accommodates larger-sized sheetswhile the second sheet cassette accommodates smaller-sized sheets.Accordingly, feeding sheets of different sizes may be switched readilyby moving second sheet cassette 30, 330, 430 between the sheet feedposition closer to sheet feeder 6, 306, 60, and the non-sheet-feedposition further away from the sheet feeder. When second sheet cassette30, 330, 430 is at the sheet feed position, sheet feeder 6, 306, 60feeds the sheets in second sheet cassette 30, 330, 430, and when secondsheet cassette 30, 330, 430 is set at the non-sheet-feed position, sheetfeeder 6, 306 feeds the sheets in first sheet cassette 3, 303, 403. Thisstructure allows the user to avoid loading and unloading the sheets orremoving second sheet cassette 30, 330, 430 from first sheet cassette 3,303, 403.

In addition, according to the first through third embodiments of thepresent invention, each of the first and second sheet cassettes isprovided, with guide unit 34 a, 34 b, 41 that guides the side edges ofthe sheets in parallel with the sheet feed direction, and thus sheets inthe first and second sheet cassettes may properly be positioned andoriented. Second sheet cassette 30, 330, 430 may be provided withcutouts 70 that allow the user to access handle 38 in order to operateguide unit 34 a, 34 b of first sheet cassette 3, 303, 403 withoutremoving the second sheet cassette 30, 330, 430 from the first sheetcassette 3, 303, 403, thereby facilitating sheet positioning in firstsheet cassette 3, 303, 403 and regulation of the sheet feed direction.

In addition, according to the first through third embodiments of thepresent invention, second sheet cassette 30, 330, 430 may be connectedmovably and pivotably to the guide hole 35 formed in side plates 3 c offirst sheet cassette to be elongated in the sheet feed direction.Accordingly, second sheet cassette 30, 330, 430 is unlikely to come offthe first sheet cassette 3, 303, 403, and readily may be inserted intoand removed from housing 2 unitarily with first sheet cassette 3, 303,403. Second sheet cassette 30, 330, 430 may be pivotable to provide alarger vertical space between the first and second sheet cassettes,facilitating reloading of the sheets in first sheet cassette 3, 303,403.

In addition, according to the first through third embodiments of thepresent invention, the sheets in second sheet cassette 30, 330, 430, aswell as sheets in the first sheet cassette 3, 303, 403, are separatedand fed by the cooperation of sheet feed roller 6 b, 60 b and maininclined separation plate 8 provided at the downstream end of firstsheet cassette 3, 303, 403 as seen in the sheet feed direction.Accordingly, the structure of sheet feed device 100, 101, 102 may besimple and compact.

According to a modified first and second sheet cassettes 103, 130,second sheet cassette 130 may be provided at its downstream end as seenin the sheet feed direction with auxiliary inclined separation plate 51that cooperates with the sheet feed roller to feed the sheets one by onetoward the recording unit. Accordingly, the sheets in second sheetcassette 130 are unlikely to be displaced and readily may be separatedand fed.

In addition, according to the first through third embodiments of thepresent invention, when second sheet cassette 30, 330, 430 is moved onfirst sheet cassette 3, 303, 403 to the non-sheet-feed position in adirection opposite to the sheet feed direction, the upstream end ofsecond sheet cassette 30, 330, 430 is located at substantially the sameas or at a more upstream position than the upstream end of the firstsheet cassette 3, 303, 403 as seen in the sheet feed direction.Accordingly, feeding the sheets in the first or second sheet cassette isreadily switched by changing the position of the second sheet cassettewith respect to the first sheet cassette.

In addition, according to the first through third embodiments of thepresent invention, when second sheet cassette 30, 330, 430 is set atsheet feed position on the first sheet cassette 3, 303, 403, secondsheet cassette 330, 330, 430 may be held to first sheet cassette 3, 303,403 by the engagement of engaging pieces 31, which project from thedownstream end of the second sheet cassette as seen in the sheet feeddirection, into positioning holes 8 b formed in main inclined separationplate 8. Accordingly, the second sheet cassette 30, 330, 430 may beprevented from being displaced from the sheet feed position, therebyensuring the stable and reliable separation and feeding of sheets in thesecond sheet cassette 30, 330, 430.

In addition, according to the first through third embodiments of thepresent invention, the second sheet cassette 30, 330, 430 comprisesholding portion 30 a for holding the sheets to be fed to recording unit7, and sheet receiver 30 b for receiving the sheets discharged fromrecording unit 7. Sheet receiver 30 b may be formed integrally withholding portion 30 a, and sheet receiver 30 b and holding portion 30 amay be shaped like a flat plate. Thus, no additional sheet receiver isneeded separately, and the sheet holding and receiving portions can besimple in structure and compact in size. When second sheet cassette 30,330, 430 is at the sheet feed position, smaller-sized sheets arereceived by the sheet receiver 30 b, and when second sheet cassette 30,330, 430 is at the non-sheet-feed position, larger-sized sheets aresupported on the leading side by sheet receiver 30 b. Accordingly, sheetreceiver 30 b may receive different-sized sheets.

In sheet feed device 100, 101 according to the first and secondembodiments of the present invention, by contact between cam follower 43and the auxiliary cam 44, sheet feed roller 6 b held by sheet feed arm 6a is movable up and down with respect to the sheets in second sheetcassette 30, 330 as second sheet cassette 30, 330 is moved back andforth with respect to sheet feed roller 6 b, that is, moved between thesheet feed position and the non-sheet-feed position. When second sheetcassette 30, 330 is at the sheet feed position on first sheet cassette3, 303, sheet feed roller 6 b is allowed to contact the uppermost one ofsheets in the second sheet cassette 30, 330. On the other hand, whensecond sheet cassette 30, 330 is away from the sheet feed position,sheet feed roller 6 b is raised and unable to contact the sheets insecond sheet cassette 30, 330. Accordingly, feeding of the sheets insecond sheet cassette 30, 330 is performed only when second sheetcassette 30, 330 is at the sheet feed position, thereby preventing sheetmisfeed or sheet jamming.

In sheet feed device 101 according to the second embodiment of thepresent invention, by the contact between end 43 a of the cam follower43 and main cam 55, sheet feed roller 6 b held by sheet feed arm 6 a ismovable up and down with respect to main inclined separation plate 8 asfirst sheet cassette 303 is moved unitarily with second sheet cassette330 with respect to sheet feed roller 6 b. Accordingly, sheet feedroller 6 b does not collide with the inclined separation plate 8 whenthe first and second sheet cassettes are unitarily inserted into andremoved from housing 2.

In sheet feed device 102 according to the third embodiment, the sheetsin first sheet cassette 403 are fed by first sheet feeder 306, while thesheets in second sheet cassette 430 are fed by second sheet feeder 60.The first and second sheet feeders are shifted between the operatingposition and the non-operating position for sheet feeding as secondsheet cassette 430 is moved back and forth with respect to the firstsheet cassette 403. Accordingly, the sheet feeders are prevented frombeing activated erroneously, thereby preventing sheet misfeed or sheetjamming.

In addition, according to the third embodiment of the present invention,each of first sheet feeder 306 and second sheet feeder 60 comprisessheet feed roller 6 b, 60 b and cam follower 43, 61. The cam followers43, 61 of the first and second sheet feeders 306, 60, respectively, maybe arranged in directions opposite to each other and perpendicular tothe sheet feed direction. Main and auxiliary cams 55, 44 contactablewith the cam follower 43 of the first sheet feeder 306 and main andauxiliary cams 55,44 contactable with cam follower 61 of second sheetfeeder 60 may be formed separately at different positions of the firstand second sheet cassette 403, 430. Accordingly, up and down movementsof each of sheet feed rollers 6 b, 60 b may be individually controlled.

In addition, according to the third embodiment of the present invention,auxiliary cam 44 that contacts the cam follower 61 of the second sheetfeeder 60 has such a shape that sheet feed roller 60 b of second sheetfeeder 60 is held at an upper position when second sheet cassette 430 ismoved back to the upstream side as seen in the sheet feed direction withrespect to first sheet cassette 403. Accordingly, sheet feed roller 60 bfor second sheet cassette 430 is prevented from being activatederroneously to feed the undesired sheets in second sheet cassette 430.

In addition, according to the third embodiment of the present invention,auxiliary cam 44 that contacts cam follower 43 of first sheet feeder 306has such a shape that sheet feed roller 6 b of first sheet feeder 306 isheld at an upper position when second sheet cassette 430 is moved forthto the downstream side as seen in the sheet feed direction with respectto first sheet cassette 403. Accordingly, sheet feed roller 6 b forfirst sheet cassette 403 is prevented from being activated erroneouslyto feed the undesired sheets in first sheet cassette 403.

In image recording apparatus 1 into which sheet feed device 100, 101,102 according to any of the embodiments of the present invention may beincorporated, recording unit 7, sheet feed path 9 a, and sheet feeder 6,306, 60 are accommodated in housing 2, and the first and second sheetcassettes are disposed at a lower position than recording unit 7 and aremoveable inward and outward with respect to housing 2. Accordingly,sheets can be reloaded easily in the first and second sheet cassettes bypulling outward the first and second sheet cassettes set in housing 2.

In addition, image recording apparatus 1 may comprise media sensor 49that detects the width of a sheet fed from the first and second sheetcassettes to recording unit 7, and cassette sensor 50 that detects theposition of second sheet cassette 30, 330, 430. Accordingly, imagerecording on a sheet of wrong size is prevented, and an erroneous sheetcassette setting at the sheet feed position is detected beforerecording, thereby avoiding wasting the sheet and the time required forsheet feed.

While the invention has been described in connection with preferredembodiments, it will be understood by those of ordinary skill in the artthat other variations and modifications of the preferred embodimentsdescribed above may be made without departing from the scope of theinvention. Other embodiments will be apparent to those skilled in theart from a consideration of the specification or practice of theinvention disclosed herein. It is intended that the specification andthe described examples only are considered as exemplary of theinvention, with the true scope of the invention being defined by thefollowing claims.

1. A sheet feed device comprising: a first sheet cassette comprising anaccommodating portion configured to accommodate a first plurality ofsheets; a second sheet cassette disposed on the first sheet cassette andconfigured to accommodate a second plurality of sheets, wherein at leastone characteristic of the first plurality of sheets is different than atleast one characteristic of the second plurality of sheets; a sheetfeeder configured to selectively feed the first plurality of sheets andthe second plurality of sheets in a sheet feed direction toward a sheetfeed path, wherein the sheet feeder comprises a first sheet feed unitcomprising a first sheet feed roller; and a sheet separator configuredto separate, one by one, the sheets fed by the sheet feeder, wherein thesecond sheet cassette is configured to move above the accommodatingportion and with respect to the sheet feeder from a first position to asecond position and from the second position to the first position,wherein the first position is associated with a sheet feed position, inwhich the second sheet cassette is positioned with respect to the firstsheet feed roller to allow the first sheet feed roller to contact thesheets in the second sheet cassette, and the second position isassociated with a non-sheet feed position, in which the second sheetcassette is positioned with respect to the first sheet feed roller toprevent the first sheet feed roller from contacting the sheets in thesecond sheet cassette, and wherein when the second sheet cassette is ina third position which is between the first position and the secondposition and in which a downstream end of the second sheet cassette isfurther downstream in the sheet feed direction than the first sheet feedroller, the first sheet feed roller is away from the sheets in the firstsheet cassette and the sheets in the second sheet cassette.
 2. The sheetfeed device according to claim 1, wherein the sheet feeder comprises asheet feed roller, the first position is associated with a sheet feedposition, in which the second sheet cassette is positioned with respectto the sheet feed roller to allow the sheet feed roller to contact thesheets in the second sheet cassette, and the second position isassociated with a non-sheet feed position, in which the second sheetcassette is positioned with respect to the sheet feed roller to preventthe sheet feed roller from contacting the sheets in the second sheetcassette.
 3. The sheet feed device according to claim 1, wherein thesheet feed unit comprises a drive shaft extending in a directionperpendicular to the sheet feed direction; a sheet feed arm extendingfrom the drive shaft in the sheet feed direction; and a cam followerextending from the sheet feed arm along an axis of the drive shaft,wherein the first feed roller is provided at an end of the sheet feedarm, wherein the second sheet cassette comprises, at a downstream sidethereof in the sheet feed direction, a holding portion that holds thesecond plurality of sheets and comprises, at an upper surface of a sideplate thereof extending in the sheet feed direction, an auxiliary camconfigured to contact the cam follower, and wherein the first sheet feedroller is configured to move up and down with respect to the holdingportion of the second sheet cassette as the second sheet cassette moveswith respect to the first sheet feed roller.
 4. The sheet feed deviceaccording to claim 3, wherein the second sheet cassette comprises a sideplate extending in the sheet feed direction, and the auxiliary cam isformed at an upper surface of the side plate of the second sheetcassette.
 5. The sheet feed device according to claim 3, wherein thesheet separator comprises an inclined separation plate disposed at adownstream end of the first sheet cassette in the sheet feed direction,and the inclined separation plate cooperates with the first sheet feedroller to selectively feed the first plurality of sheets and the secondplurality of sheets one by one toward the sheet feed path, wherein thefirst sheet cassette comprises, at an upper surface of a side platethereof extending along the sheet feed direction, a main cam configuredto contact the cam follower, and wherein the first sheet feed roller isconfigured to move up and down with respect to the inclined separationplate as the first sheet cassette moves, unitarily with the second sheetcassette, with respect to the first sheet feed roller.
 6. The sheet feeddevice according to claim 5, wherein the first sheet cassette comprisesa side plate extending in the sheet feed direction, and the main cam isformed at an upper surface of the side plate of the first sheetcassette.
 7. The sheet feed device according to claim 1, wherein thesheet feeder further comprises a second sheet feed unit that is locatedin parallel with the first sheet feed unit in a direction perpendicularto the sheet feed direction, and the sheet separator selectivelycooperates with the first sheet feed unit to feed the second pluralityof sheets and cooperates with the second sheet feed unit to feed thefirst plurality of sheets one by one toward the sheet feed path.
 8. Thesheet feed device according to claim 7, wherein the second sheet feedunit comprises a second sheet feed roller, and each of the first and thesecond sheet feed units comprises a drive shaft extending in a directionperpendicular to the sheet feed direction; a sheet feed arm extendingfrom the drive shaft in the sheet feed direction; and a cam followerextending from the sheet feed arm along an axis of the drive shaft, andwherein each of the first and the second sheet feed rollers are providedat an end of a corresponding one of the sheet feed arms, wherein thefirst sheet cassette comprises, at upper surfaces of side plates thereofextending in the sheet feed direction, main cams configured to contactthe cam followers of the first sheet feed unit and the second sheet feedunit, respectively, and the second sheet cassette comprises, at uppersurfaces of side plates thereof extending in the sheet feed direction,auxiliary cams configured to contact the cam followers of the firstsheet feed unit and the second sheet feed unit, respectively, andwherein the first and the second sheet feed rollers are configured tomove up and down as the first sheet cassette moves unitarily with thesecond sheet cassette with respect to the first and the second sheetfeed rollers and as the second sheet cassette moves with respect to thefirst sheet cassette.
 9. The sheet feed device according to claim 8,wherein the sheet separator comprises an inclined separation platedisposed at a downstream end of the first sheet cassette in the sheetfeed direction, and the inclined separation plate selectively cooperateswith the first sheet feed roller to fee the second plurality of sheetsand cooperates with the second sheet feed roller to feed the firstplurality of sheets one by one toward the sheet feed path, and whereinthe first and the second sheet feed rollers are configured to move withrespect to the inclined separation plate as the first sheet cassettemoves, unitarily with the second sheet cassette, with respect to thefirst and the second sheet feed rollers.
 10. The sheet feed deviceaccording to claim 8, wherein the cam follower of the first sheet feedunit and the cam follower of the second sheet feed unit are arranged indirections opposite to each other and perpendicular to the sheet feeddirection.
 11. The sheet feed device according to claim 8, wherein ashape of the auxiliary cam that contacts the cam follower of the firstsheet feed unit is selected such that the first sheet feed roller isheld at an upper position when the second sheet cassette moves to thenon-sheet feed position at an upstream side in the sheet feed directionwith respect to the first sheet cassette.
 12. The sheet feed deviceaccording to claim 8, wherein a shape of the auxiliary cam that contactsthe cam follower of the second sheet feed unit is selected such that thesecond sheet feed roller is held at an upper position when the secondsheet cassette moves to the sheet feed position at a downstream side inthe sheet feed direction with respect to the first sheet cassette. 13.The sheet feed device according to 1, wherein the second sheet cassettecomprises a cam, the first sheet feed unit further comprises a camfollower coupled to the first sheet feed roller, and the cam isconfigured to contact the cam follower and to move up the first sheetfeed roller when the second sheet cassette is in the third position.